In most payload architectures, the repeaters installed on the satellites comprise a large number of independent RF radiofrequency channels each comprising an item of equipment for preamplifying the radiofrequency signals received by the repeater, said equipment being designed to provide the power required at the input of a traveling wave tube. This traveling wave tube is a microwave-frequency power amplifier used to retransmit the received signals to a subscriber. It is made to operate close to its saturation power, which causes a nonlinear response from the tube, this nonlinear response being able to be corrected by a linearizer function that may be installed in the item of preamplification equipment placed upstream of the tube, the item of preamplification equipment then being called a linearizer channel amplifier.
The linearizer-channel amplifier device dedicated to each RF system comprises an amplifier module, possibly a linearizer module and a remote control and telemetry module. The remote control and telemetry module controls the linearizer-channel amplifier device and manages the telecommunications with a ground station. The remote control and telemetry module comprises a remote control portion which programs the amplifier module and the linearizer in order to adapt it to the conditions of use determined by the traffic of data to be transmitted and in general by the requirements specific to the link budget, and a telemetry portion responsible for managing and transmitting the measurements made by the linearizer-channel amplifier device to the ground station. The remote control and telemetry module may also manage and transmit telemetries originating from other items of equipment of the satellite such as, for example, those of the system for powering the traveling wave tubes.
Since the repeaters comprise a large number of channels each comprising a dedicated linearizer-channel amplifier device and since each linearizer-channel amplifier device comprises several independent modules, this architecture has problems of space requirement and production cost, all the greater since there is a large number of channels.